1. Field of the Invention
The present invention relates to an apparatus for placing electronic components onto circuit boards, and a component placement method executed by the apparatus.
2. Description of the Related Art
The variety of kinds of electronic components to be placed on circuit boards has increased recently. Accordingly, an apparatus that can handle various electronic components from micro-chip components to long connectors, etc. is strongly demanded. An example of a conventional apparatus of the above type will be described below with reference to FIG. 10. FIG. 10 shows a total view of a conventional component placement apparatus 20. In FIG. 10, reference numeral 1 indicates a transfer device for carrying in and out an electronic circuit board 2 with respect to the component placement apparatus 20 and positioning the circuit board 2 when electronic components are placed on the circuit board 2. Reference numeral 3 indicates a reel-type component feed device including reels 4 to which a tape temporarily securely holding the electronic components is wound. The feed device sends the tape from the reel 4 thereby feeding the electronic components one by one. A tray-type component feed device 5 is also set in the apparatus 20 to feed electronic components, and the electronic components are aligned in a grid pattern on a tray 6. Reference number 7 indicates a placement head having a component hold part 8 for holding a hold member 13 which sucks so as to hold the electronic components supplied from the reel-type component feed device 3 and the tray-type component feed device 5. According to the component placement apparatus 20, the hold member 13 is a nozzle that can suck the electronic component. Reference numeral 9 indicates an XY-robot for moving the placement head 7 in X, Y-directions orthogonal to each other with a plant to an optional position and positioning the placement head 7. Reference numeral 10 indicates a component recognition camera for measuring a suction attitude of the electronic component held by the hold member 13. Reference numeral 11 indicates a tool change part equipped with one or a plurality of hold members 13 replaced with the hold member 13 set at the component hold part 8. Reference numeral 12 indicates a control device connected to the above transfer device 1, reel-type component feed device 3, tray-type component feed device 5, placement head 7, XY-robot 9, component recognition camera 10, and tool change part 11 for controlling operations of these devices and the entire component placement apparatus 20.
In the above component placement apparatus 20, the hold member 13 sucks so as to hold the electronic components. However, the apparatus may be adapted to hold the electronic components, for instance, mechanically by a chuck mechanism. Although only one component hold part 8 is shown at the placement head 7 in FIG. 10, actually, a plurality of component hold parts 8 are arranged which are omitted in the illustration. Needless to say, the placement head 7 may be designed to keep only one component hold part 8.
The conventional component placement apparatus 20 of the above constitution operates in a manner as will be described below.
The hold members 13 of the placement head 7 are set as the component feed device 3 or component feed device 5 by the XY-robot 9. Each of the hold members 13 is lowered by the component hold part 8 in a Z direction orthogonal to the X, Y-directions to suck an electronic component to be placed on the circuit board 2. After the sucking, each hold member 13 is moved up by the component hold part 8. A plurality of electronic components held by the hold members 13 are sequentially moved by the XY-robot 9 over the component recognition camera 10. The component recognition camera 10 picks up the suction attitude of each electronic component at the hold member 13. Information on the recognized images is sent to the control device 12. The control device 12, after taking the information on the recognized images, calculates an amount of correction for each electronic component on the basis of an amount of displacement of the suction attitude from a placement attitude on the circuit board 2, and rotates the hold member 13 based on the correction amount about an axis in the Z direction. The control device 12 moves the XY-robot 9 to position the placement head 7 over the circuit board 2 and moves each component hold part 8 so that the electronic components are correctly placed sequentially at predetermined positions on the circuit board 2.
In the case where the hold member 13 not corresponding to the electronic component to be placed on the circuit board 2 is accidentally set at the component hold part 8, the XY-robot 9 is moved to move the placement head 7 over the tool change part 11 and this hold member 13 not corresponding to the electronic component to be placed is detached and retained at a vacant tool hold portion at the tool change part 11. The component hold part 8 is then moved to a tool hold portion, where the other hold member 13 corresponding to the electronic component to be placed is caught. The hold member 13 corresponding to the electronic component to be placed is thus set to the component hold part 8.
The component hold part 8 with the correct hold member 13 is moved to a feed position for the electronic component to be placed next and the above-described sequence of operations from suction to placement is repeated.
Electronic components of various kinds are sequentially placed in this manner on the circuit board 2.
The tool change part 11 will be depicted with reference to FIGS. 11 and 12. The tool change part 11 includes a holding mechanism (not shown) capable of holding the hold members 13. Each hold member 13 is inserted at a predetermined tool hold portion 14 corresponding to each hold member 13. Sensors 15 are installed at the tool hold portions 14 to detect the presence/absence of the hold member 13. Each sensor 15 is connected electrically to the control device 12. Thus the control device 12 can recognize whether or not the predetermined hold members 13 are set at the tool hold portions corresponding to the predetermined hold members 13. The sensor 15 is, specifically, a proximity sensor, a limit switch or the like known sensor.
The conventional tool change part 11 constituted as above has drawbacks. According to the related art, before starting the component placement apparatus 20, necessary hold members 13 are on standby at the predetermined tool hold portions 14 at the tool change part 11, and information on the presence/absence of the hold members 13 from the sensors 15 is recognized by the control device 12. That is, the sensor 15 is installed for each of the tool hold portions 14, thereby raising costs and making the wiring complicated. In order to distinguish the types of hold members 13 kept at the component hold parts 8, an increasing number of sensors 15 or a plurality of expensive sensors are necessitated at the tool change part.
The present invention is devised to solve the above problems and has for its object to provide a component placement apparatus that can obtain information on the presence/absence of hold members inexpensively and easily, and a component placement method carried out by the component placement apparatus.
In order to achieve the aforementioned objective, a component placement apparatus is provided according to a first mode of the present invention. The apparatus includes a placement head having a hold member that is detachable and replaceable corresponding to a component to be held for placing the component held by the hold member at an object to be placed. A hold member change part has a replacement hold member that can be fitted to the placement head where the hold member and the replacement hold member are exchanged by the placement head. The replacement hold member holds another component to place the other component at the object. The placement head has a replacement hold member detector for detecting presence/absence of the replacement hold member at the hold member change part.
Further, the replacement hold member detector detects the type of replacement hold member (type information) in addition to detecting the presence/absence of the replacement hold member.
Further, the component placement apparatus comprises a control device for making a judgement whether or not the replacement hold member corresponding to the other component to be placed at the object to be placed is present at the hold member change part on the basis of the type information of the replacement hold member corresponding to the other component to be placed at the object to be placed. The type information is sent out from the replacement hold member detector.
The type information is attached to the replacement hold member in the form of a type information indicator, and the replacement hold member detector optically reads the type information indicator.
The control device further makes a location and a type of each replacement hold member at the hold member change part correspond to each other on the basis of the information sent out from the replacement hold member detector.
A component placement method according to a second mode of the present invention includes scanning a replacement hold member set at a hold member change part so as to detect the presence/absence of the replacement hold member. It is then decided whether or not a hold member is exchangeable with the replacement hold member corresponding to a component to be held on the basis of the scanning. The hold member is exchanged with the replacement hold member corresponding to the component to be held and the component to be held with the replacement hold member is held. The component held with the replacement hold member is placed at an object to be placed.
According to the component placement apparatus in the first mode of the present invention and the component placement method in the second mode of the present invention, the replacement hold member detector is installed at the placement head to detect the presence/absence of replacement hold members at the hold member change part. The presence/absence of the replacement hold members is detected through scanning over the hold member change part. A sensor is thus eliminated from the hold member change part holding many kinds of components. A simple and inexpensive constitution is achieved.